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Structural Colors Enabled by Lattice Resonance on Silicon Nitride Metasurfaces
摘要： Artificial color pixels based on dielectric Mie resonators are appealing for scientific research as well as practical design. Vivid colors are imperative for displays and imaging. Dielectric metasurface-based artificial pixels are promising candidates for developing flat, flexible, and/or wearable displays. Considering the application feasibility of artificial color pixels, wide color gamuts are crucial for contemporary display technology. To achieve a wide color gamut, ensuring the purity and efficiency of nanostructure resonance peaks in the visible spectrum is necessary for structural color design. Low-loss dielectric materials are suitable for achieving vivid colors with structural color pixels. However, high-order Mie resonances prevent color pixels based on dielectric metasurfaces from efficiently generating highly saturated colors. In particular, fundamental Mie resonances (electric/magnetic dipole) for red can result in not only a strong resonance peak at 650 nm, but also high-order Mie resonances at shorter wavelengths, which reduces the saturation of the target color. To address these problems, we fabricated silicon nitride metasurfaces on quartz substrates and applied Rayleigh anomalies at relatively short wavelengths to successfully suppress high-order Mie resonances, thus creating vivid color pixels. We performed numerical design, semianalytic considerations, and experimental proof-of-concept examinations to demonstrate the performance of the silicon nitride metasurfaces. Apart from traditional metasurface designs that involve transmission and reflection modes, we determined that lateral light incidence on silicon nitride metasurfaces can provide vivid colors through long-range dipole interactions; this can thus extend the applications of such surfaces to eyewear displays and guided-wave illumination techniques.
关键词： metasurfaces,Mie resonances,lattice resonances,color,silicon nitride,high-refractive-index nanostructures
更新于2025-09-23 15:19:57
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Lasing from Finite Plasmonic Nanoparticle Lattices
摘要： Small for lasers can generate coherent in vivo cellular imaging, and solid-state integrated photonics, lighting. Unlike conventional lasers, plasmonic lasers can generate coherent light at subwavelength scales, although cavity architectures based on metal ?lms and semiconducting gain exhibit large radiative losses and lack directional emission. In contrast, 2D metal nanoparticle arrays surrounded by organic dyes can support lasing with high directionality at the relationship between the number of nanoparticles in a ?nite lattice and their lasing emission characteristics is unknown. Here we show that the number of units in 2D gold nanoparticle lattices is critical to generate robust cavity resonances and lasing emission. Narrower lattice plasmons associated with stronger electromagnetic near ?elds are observed as the nanoparticle number increases. Experimentally, we demonstrate lasing from a 30 × 30 nanoparticle lattice. Semiquantum modeling indicates lower lasing thresholds and faster population inversion dynamics with higher nanoparticle numbers. These results suggest that ?nite lattices of nanoparticles integrated with gain can function as independent, coherent light sources for optical multiplexing and lab-on-a-chip applications.
关键词： metal nanoparticle lattices,?nite size,surface lattice resonances,small lasers,lattice plasmons
更新于2025-09-23 15:19:57
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Dual-Wavelength Lasing in Quantum-Dot Plasmonic Lattice Lasers
摘要： Arrays of metallic particles patterned on a substrate have emerged as a promising design for on-chip plasmonic lasers. In past examples of such devices, the periodic particles provided feedback at a single resonance wavelength, and organic dye molecules were used as the gain material. Here, we introduce a flexible template-based fabrication method that allows a broader design space for Ag particle-array lasers. Instead of dye molecules, we integrate colloidal quantum dots (QDs), which offer better photostability and wavelength tunability. Our fabrication approach also allows us to easily adjust the refractive index of the substrate and the QD-film thickness. Exploiting these capabilities, we demonstrate not only single-wavelength lasing but dual-wavelength lasing via two distinct strategies. First, by using particle arrays with rectangular lattice symmetries, we obtain feedback from two orthogonal directions. The two output wavelengths from this laser can be selected individually using a linear polarizer. Second, by adjusting the QD-film thickness, we use higher-order transverse waveguide modes in the QD film to obtain dual-wavelength lasing at normal and off-normal angles from a symmetric square array. We thus show that our approach offers various design possibilities to tune the laser output.
关键词： surface lattice resonances,dual-wavelength laser,colloidal quantum dots,plasmonics,nanolaser,template stripping,polarization
更新于2025-09-23 15:19:57
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Narrow plasmonic surface lattice resonances with preference to asymmetric dielectric environment
摘要： Plasmonic surface lattice resonances (SLRs) supported by metal nanoparticle arrays exhibit narrow linewidths and enhanced localized ?elds and thus are attractive in diverse applications including nanolasers, biochemical sensors and nonlinear optics. However, it has been shown that these SLRs have much worse performance in a less symmetric environment, hindering their practical applications. Here, we propose a novel type of narrow SLRs that is supported by metal-insulator-metal nanopillar arrays and that has better performance in a less symmetric dielectric environment. When the dielectric environment is as asymmetric as the air/polymer environment with a refractive index contrast of 1.0/1.52, the proposed SLRs have high quality factors of 62 under normal incidence and of 147 under oblique incidence in the visible regime. We attribute these new SLRs to Fano resonance between an in-plane dipole and an out-of-plane quadrupole (or dipole) that are respectively supported by the two metal ridges under normal (or oblique) incidence. We also show that the resonance wavelength can be tuned by varying the geometric sizes or by changing the angle of incidence. By doing this, we clarify the conditions for the formation of the proposed SLRs and illustrate their attractive merits in sensing applications. We expect that this new SLR can open up applications in asymmetric dielectric environments.
关键词： sensing applications,asymmetric dielectric environment,Plasmonic surface lattice resonances,metal-insulator-metal nanopillar arrays,Fano resonance
更新于2025-09-23 15:19:57
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Ultrahigh brightening of infrared PbS quantum dots via collective energy transfer induced by a metal-oxide plasmonic metastructure
摘要： We demonstrate a solution-processed heterojunction interface formed via addition of a thin buffer layer of CdSe/ZnS quantum dots to a functional metal oxide plasmonic metastructure (FMOP) can set up a collective inter-quantum dot energy transport process, significantly enhancing the emission of infrared PbS quantum dots. The FMOP includes a Schottky junction, formed via deposition of a Si layer on arrays of Au nanoantennas, and a Si/Al oxide charge barrier. We show when these two junctions are separated from each other by about 15 nm and the CdSe/ZnS quantum dot buffer layer is placed in touch with the Si/Al oxide junction, the quantum efficiency of an upper layer of PbS quantum dots can increase by about one order of magnitude. These results highlight a unique energy circuit formed via collective coupling of the CdSe/ZnS quantum dots with the hybridized states of plasmons and diffraction modes of the arrays (surface lattice resonances) and coupling between such resonances with PbS QDs via lattice-induced photonic modes.
关键词： exciton-plasmon coupling,plasmons,collective,PbS quantum dots,metallic nanoantennas,surface lattice resonances,energy transfer
更新于2025-09-23 15:19:57
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Quantum Dot-Plasmon Lasing with Controlled Polarization Patterns
摘要： The tailored spatial polarization of coherent light beams is important for applications ranging from microscopy to biophysics to quantum optics. Miniaturized light sources are needed for integrated, on-chip photonic devices with desired vector beams; however, this issue is unresolved because most lasers rely on bulky optical elements to achieve such polarization control. Here, we report on quantum dot-plasmon lasers with engineered polarization patterns controllable by near-field coupling of colloidal quantum dots to metal nanoparticles. Conformal coating of CdSe?CdS core?shell quantum dot films on Ag nanoparticle lattices enables the formation of hybrid waveguide-surface lattice resonance (W-SLR) modes. The sidebands of these hybrid modes at nonzero wavevectors facilitate directional lasing emission with either radial or azimuthal polarization depending on the thickness of the quantum dot film.
关键词： nanolaser,band structure engineering,radially and azimuthally polarization states,surface lattice resonances,colloidal quantum dots,lattice plasmons,waveguide
更新于2025-09-19 17:13:59
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Diffractive dipolar coupling in non-Bravais plasmonic lattices
摘要： Honeycomb plasmonic lattices are paradigmatic examples of non-Bravais lattices. We experimentally measure surface lattice resonances in effectively free-standing honeycomb lattices composed of silver nanospheres. By combining numerical simulations with analytical methods, we analyze the dispersion relation and the near-field properties of these modes along high symmetry trajectories. We find that our results can be interpreted in terms of dipole-only interactions between the two non-equivalent triangular sublattices, which naturally lead to an asymmetric near-field distribution around the nanospheres. We generalize the interaction between the two sublattices to the case of variable adjacent interparticle distance within the unit cell, highlighting symmetry changes and diffraction degeneracy lifting associated to the transition between Bravais and non-Bravais lattices.
关键词： honeycomb plasmonic lattices,surface lattice resonances,non-Bravais lattices,diffraction degeneracy lifting,silver nanospheres,near-field properties,dipole-only interactions
更新于2025-09-19 17:13:59
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Engineering Directionality in Quantum Dot Shell Lasing Using Plasmonic Lattices
摘要： We report how the direction of quantum dot (QD) lasing can be engineered by exploiting high-symmetry points in plasmonic nanoparticle (NP) lattices. The nanolaser architecture consists of CdSe?CdS core?shell QD layers conformally coated on two-dimensional square arrays of Ag NPs. Using waveguide-surface lattice resonances (W-SLRs) near the Δ point in the Brillouin zone as optical feedback, we achieved lasing from the gain in CdS shells at off-normal emission angles. Changing the periodicity of the plasmonic lattices enables other high-symmetry points (Γ or M) of the lattice to overlap with the QD shell emission, which facilitates tuning of the lasing direction. We also increased the thickness of the QD layer to introduce higher-order W-SLR modes with additional avoided crossings in the band structure, which expands the selection of cavity modes for any desired lasing emission angle.
关键词： band structure engineering,laser directionality,surface lattice resonances,colloidal quantum dots,lattice plasmons,waveguide
更新于2025-09-16 10:30:52
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Towards Efficient Nonlinear Plasmonic Metasurfaces
摘要： Nonlinear processes are important in many fields of photonics ranging from biomedical imaging to ultrashort pulse generation. Progress in nanophotonics and metamaterials has created a growing demand for nanoscale nonlinear optical components. However, it is difficult to answer this demand by using traditional materials motivating the search for alternatives approaches. Nonlinear plasmonics has emerged as a viable solution for enabling efficient and nanoscale nonlinear optics. Despite steady progress, so far achieved conversion efficiencies of metamaterials have not yet rivalled conventional nonlinear materials. Here, we discuss our recent progress in development of efficient nonlinear plasmonic metamaterials. Focus is on metasurfaces utilizing collective responses known as surface lattice resonances, which can be used to dramatically boost nonlinear responses of metasurfaces.
关键词： nonlinear metamaterials,surface lattice resonances,metasurfaces,frequency conversion
更新于2025-09-16 10:30:52
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Manipulating Light–Matter Interactions in Plasmonic Nanoparticle Lattices
摘要： Rationally assembled nanostructures exhibit distinct physical and chemical properties beyond their individual units. Developments in nanofabrication techniques have enabled the patterning of a wide range of nanomaterial designs over macroscale (>in.2) areas. Periodic metal nanostructures show long-range diffractive interactions when the lattice spacing is close to the wavelength of the incident light. The collective coupling between metal nanoparticles in a lattice introduces sharp and intense plasmonic surface lattice resonances, in contrast to the broad localized resonances from single nanoparticles. Plasmonic nanoparticle lattices exhibit strongly enhanced optical fields within the subwavelength vicinity of the nanoparticle unit cells that are 2 orders of magnitude higher than that of individual units. These intense electromagnetic fields can manipulate nanoscale processes such as photocatalysis, optical spectroscopy, nonlinear optics, and light harvesting. This Account focuses on advances in exciton?plasmon coupling and light?matter interactions with plasmonic nanoparticle lattices. First, we introduce the fundamentals of ultrasharp surface lattice resonances; these resonances arise from the coupling of the localized surface plasmons of a nanoparticle to the diffraction mode from the lattice. Second, we discuss how integrating dye molecules with plasmonic nanoparticle lattices can result in an architecture for nanoscale lasing at room temperature. The lasing emission wavelength can be tuned in real time by adjusting the refractive index environment or varying the lattice spacing. Third, we describe how manipulating either the shape of the unit cell or the lattice geometry can control the lasing emission properties. Low-symmetry plasmonic nanoparticle lasing responses, and multiscale plasmonic superlattices—finite patches of lattices can show polarization-dependent nanoparticles grouped into microscale arrays—can support multiple plasmon resonances for controlled multimodal nanolasing. Fourth, we discuss how the assembly of photoactive emitters on the nanocavity arrays behaves as a hybrid materials system with enhanced exciton?plasmon coupling. Positioning metal?organic framework materials around nanoparticles produces mixed photon modes with strongly enhanced photoluminescence at wavelengths determined by the lattice. Deterministic coupling of quantum emitters in two-dimensional materials to plasmonic lattices leads to preserved single-photon emission and reduced decay lifetimes. Finally, we highlight emerging applications of nanoparticle lattices from compact, fully reconfigurable imaging devices to solid-state emitter structures. Plasmonic nanoparticle lattices are a versatile, scalable platform for tunable flat optics, nontrivial topological photonics, and modified chemical reactivities.
关键词： nanoscale lasing,surface lattice resonances,exciton?plasmon coupling,light?matter interactions,plasmonic nanoparticle lattices
更新于2025-09-16 10:30:52